The day function hours.

The number of hours of daylight in anchorage,north latitude of alaska .

Convert latitude from seconds to normal degree representation angle : .

(a).

Summer solstice .

Calculate the function .

Substitute the values and in the above function.

.

.

.

.

Convert angle from degrees to radians.

The day function hours.

Substitute the value  in above function.

Daylight is .

(b).

Vernal equinox .

Calculate the function .

Substitute the values and in the above function.

Convert angle from degrees to radians.

. 

.

The day function hours 

Substitute the value in above function.

.

.

.

.

Daylight is .

(c).

July 4.

Calculate .

Convert latitude from seconds to normal degree representation angle :

Substitute and .

.

Convert angle from degrees to radians.

The day function hours.

Daylight is .

The number of hours of daylight in anchorage,north latitude of alaska for following dates :

(a) On Summer solstice is .

(b) On  Vernal equinox is .

(c) On July 4 is .